6 Mobility
Short Description
RL20 mobility Parameter...
Description
Mobility in LTE Radio Network Design for Roll-Outs (RNDR) (RNDR) Connected Mode Mobility Idle Mode Mobility
Soc Classification level
Connected Mode Mobility
Soc Classification level
Connected Mode Mobility • Overview – Mobility supported in different releases – Mobility triggers – Mobility Thresholds • Connected Mode Mobility types – Intra and Inter-frequency Handovers – S1 Handover – IRAT Handover to WCDMA – eNACC to GSM – RRC Connection Release with Redirect – CS Fallback
Soc Classification level
Overview • Procedures supported: – Handover: Transfer of an ongoing call/data session from a cell to another without call interruption. Handovers in LTE are: o
Network controlled
o
UE assisted
o
Hard handovers: Only a connection exist to one cell at a time
Similar to handover handover,, but requir requires es connection connection release release prior prior to the – Redirection: Similar transfer the ongoing call
– Cell change: procedure dedicated for call transfer from LTE to GSM; it requires connection release Licensing:
• All IRAT HO, inter-frequency HO, CSFB to UTRAN/GERAN UTRAN/GERA N via redirect and S1 handovers are optional features:
• When enabled they are activated for the whole eNodeB • If deactivated the eNB does not configure UE to measure other technologies/ frequencies so handover is not triggered Soc Classification level
Mobility supported in different Releases FDD:
RL10
RL20
RL30
Intra eNB Handover
Inter Frequency HO (intra eNB and via X2)
IRAT Handover: LTE to WCDMA
Inter eNB HO via X2 interface
S1 based HO
eNACC from LTE to GSM
RRC connection Release with Redirect
CSFB to UTRAN or GSM via Redirect
TDD:
RL15TD
RL25TD
Intra eNodeB Handover
IRAT Handover: LTE to WCDMA
Inter eNodeB Handover via X2
eNACC from LTE to GSM
Inter frequency handover (intra eNodeB and via X2)
CSFB to UTRAN or GSM via Redirect
RRC connection Release with Redirect Inter eNodeB Handover via S1
Soc Classification level
Mobility Triggers (1/3) • Mobility is handled via events triggering. 3GPP defines following events: Event A1 Serving becomes better than threshold Event A2 Serving becomes worse than threshold
Events A4 and B1 are not supported in RL30
Event A3 Neighbour becomes offset better than serving
Event A4 Neighbour becomes better than threshold Event A5 Serving becomes worse than threshold1 and neighbour becomes better than threshold2
Event B1 Inter RAT neighbour becomes better than threshold Event B2 Serving becomes worse than threshold1 and inter RAT neighbour becomes better than threshold2 Soc Classification level
Mobility Triggers (2/3) • Event A2/A1: RSRP of serving cell is down/up-crossing certain RSRP threshold (threshold2a/ threshold1)
• Event A3 (better cell HO) : RSRP of neighbour cell is a predefined offset better than RSRP of serving (for intra and inter frequency HOs)
• Event A5 (coverage HO): RSRP of serving cell is down-crossing certain threshold, while RSRP of neighbour cell is up-crossing an other threshold (for intra and inter frequency HOs)
threshold3a threshold3
neighbour Soc Classification level
Mobility Triggers (3/3) Inter-RAT measurements (GERAN or UMTS supported in RL30)
• Event B2: Serving cells RSRP down-crossing threshold1, while neighbour cell RSSI or CPICH RSCP or CPICH E c/No up-crossing threshold2
• Triggers for Inter-RAT reports are: – RSSI in case of GERAN – CPICH RSCP or CPICH EC /N0 in case of UMTS Signal Level B2 trigger B2 thold 2
Inter-RAT Neighbour cell signal
B2 thold 1 RSRP serving move direction Soc Classification level
Handover Thresholds Measurement Activations • Threshold 1 (Th1): UE does not perform measurements of neighbour cells when the serving cell RSRP is above Threshold1 (Th1)
• Thresholds 2 (Th2_interfreq/Th2_WCDMA/Th2_GSM): UE starts performing measurement gaps when one of the Th2 events is reported to the eNodeB in a measurement report. Event A2
• Threshold2a (Th2a): Measurement gaps are cancelled if serving cell RSRP rises above Th2a. Event A1
• Threshold 4 (Th4):RRC Connection Release with redirection is triggered if no suitable intra or inter frequency/IRAT cells are found. Event A2
threshold2InterFreq Event A2
No m easurements except serving cell
Intra –LTE measurements
Intra –LTE + Inter Freq measurements
Intra –LTE + Inter Freq + WCDMA + GSM measurements RRC Intra –LTE + Inter Connection Freq + WCDMA Release and measurements re-direction
RSRP (dBm) Th1
Soc Classification level
Th2a
Th2_InterFreq
Th2_WCDMA
Th2_GSM
Th4
Threshold1
Threshold2a
threshold2WCDMA threshold2GERAN
S-measure
a1-threshold
Event A2
Event A2
threshold4 Event A2
Intra- and Inter-frequency Handover Thresholds Serving cell (not including neighbour cell thresholds) • Example values:
Soc Classification level
Mobility thresholds comments RRC_connected mode • LTE thresholds are relative to -140 dBm. This means if for example threshold3 is set to 21, the RSRP value is (-140+21=) -119dBm
• The following restrictions need to be fulfilled: – Threshold4 < Threshold3 < Threshold2_xxxx Ms + a3Offset
Parameters involved:
hysA3Offset
Signal level
intra-frequency neighbour cell ( Mn )
Hysteresis of HO Margin LNCEL; 0..15; 0.5; - dB
(RSRP)
hysA3Offset
a3Offset Better cell HO margin for RSRP
a3Offset
LNCEL; -15…15; 0.5; - dB serving cell ( Ms ) time
Event A3 condition fullfilled, UE sends measurement report
Soc Classification level
a3ReportInterval
a3TimeToTrigger Measurement Report
Measurement Report
a3TimeToTrigger
a3ReportInterval
LNCEL; 0..5120ms; -; 320ms(8)
LNCEL; 120ms..60 min; -; 240ms (1)
A3 event based Handover Inter-Frequency • Inter-frequency better coverage/quality based (A3) handover event evaluation Mn – hysA3OffsetRsr(p/q)InterFreq > Ms + a3OffsetRsr(p/q)InterFreq measQuantInterFreq Signal level (RSRP or RSRQ)
def. which quantity to use for event A3 LNHOIF; RSRP, RSRQ; both; RSRP
hysA3OffsetRsrp/qInterFreq
inter-frequency neighbour cell ( Mn )
Hysteresis of HO Margin LNHOIF; 0..15; 0.5; - dB
hysA3OffsetRsr(p/q)InterFreq
a3OffsetRsrp/qInterFreq
a3OffsetRsr(p/q)InterFreq
Better cell HO margin for RSRP/Q LNHOIF; 0..15; 0.5; - dB serving cell ( Ms ) time
Event A3 condition fullfilled, UE sends measurement report
Soc Classification level
a3TimeToTriggerRsr(p/q)InterFreq Measurement Report
a3ReportIntervalRsr ( p/q)InterF req Measurement Report
a3TimeToTriggerRsrp/qInterFreq
a3ReportIntervalRsrp/qInterFreq
LNHOIF; 0..5120ms; -; not used
LNHOIF; 120ms..60 min; -; not used
A5 event based Handover Intra-Frequency • Intra-frequency coverage based (A5) handover event evaluation Ms + hysThreshold3 < threshold3
Parameters involved:
and Mn – hysThreshold3 > threshold3a Signal level (RSRP)
hysThreshold3
intra-frequency neighbour cell ( Mn)
hysThreshold3
Hysteresis of HO Margin LNCEL; 0..15; 0.5; - dB
threshold3a LNCEL; 0..97; 1; - dB
threshold3 LNCEL; 0..97; 1; - dB
hysThreshold3 serving cell ( Ms ) time event A5 condition fullfilled UE sends measurement report
a5TimeToTrigger
a5TimeToTrigger Soc Classification level
LNCEL; 0..5120ms; -;320ms
Measurement Report
Measurement Report
a5ReportInterval LNCEL; 120ms..60 min; 240ms
A5 event based Handover Inter-Frequency • Inter-frequency coverage based (A5) handover event evaluation Ms + hysThreshold3InterFreq < threshold3InterFreq
and Mn – hysThreshold3InterFreq > threshold3aInterFreq Signal level
inter-frequency neighbour cell ( Mn)
hysThreshold3InterFreq
(RSRP)
Hysteresis of HO Margin
hysThreshold3InterFreq
LNHOIF; 0..15; 0.5; - dB
threshold3aInterFreq LNHOIF; 0..97; 1; - dB
threshold3InterFreq LNHOIF; 0..97; 1; - dB
hysThreshold3InterFreq serving cell ( Ms ) time event A5 condition fullfilled UE sends measurement report
a5TimeToTriggerInterFreq
a5TimeToTriggerInterFreq Soc Classification level
LNHOIF; 0..5120ms; -; -
Measurement Report
Measurement Report
a5ReportIntervalInterFreq LNHOIF; 120ms..60 min; -;
Example of successful intra-freq HO
Step 1: UE sends measurement report on PCI 274 Soc Classification level
Example of successful intra-freq HO
Step 2: UE gets RRCConnectionReconfiguration on DL and replies with an RRCConnectionReconfigurationComplete on UL Note that for a successful HO, this happens twice. The first RRCConnectionReconfiguration comes from the source cell and the second one from the target Soc Classification level
message c1 : rrcConnectionReconfiguration : {
Measurement Reports
rrcConnectionReconfiguration-r8 : { measConfig { measObjectToAddModList {
measIdToAddModList
{
{
measObjectId 1,
{
measObject measObjectEUTRA :
measId 1,
{
measObjectId 1,
carrierFreq 2075,
reportConfigId 1 },
allowedMeasBandwidth mbw25,
{
presenceAntennaPort1 TRUE,
• Measurement reports
reportConfigId 2 }, quantityConfig
a measurement Object (e.g. a frequency) and a reportConfig (an Event)
Soc Classification level
reportConfigId 2,
},
• A measId is defined by
configuration information is sent to the UE in the RRC Connection Reconfiguration Msg.
}
measObjectId 1,
refer to a measurement Id (measId)
• Measurement
neighCellConfig '00'B
measId 2,
reportConfig reportConfigEUTRA : { triggerType event :
{ quantityConfigEUTRA
{
{
eventId eventA5 :
}
{ a5-Threshold1 threshold-RSRP : 30,
},
a5-Threshold2 threshold-RSRP : 32
measGapConfig release : NULL,
}, s-Measure 90,
hysteresis 0, timeToTrigger ms640 }, triggerQuantity rsrp, reportQuantity sameAsTriggerQuantity, maxReportCells 8, reportInterval ms240, reportAmount infinity
Connected mode mobility Exercise: inter-frequency A3 • An operator has an existing LTE network on 2600MHz and on 1800MHz • LTE1800MHz network has more sites than 2600MHz network. They have 20MHz BW on 2600 and only 10MHz BW on 1800, so they want to keep the traffic as long as possible on the 2600MHz layer
• For 1800MHz cells, LNHOIF settings towards the 2600MHz layer are as follows: – LNHOIF:hysA3OffsetRsrpInterFreq = 2dB – LNHOIF:a3OffsetRsrpInterFreq = 2dB Exercise
1. Define suitable values for a3OffsetRsrpInterFreq and hysA3offsetRsrpInterFreq for the LTE2600 cells towards the 1800MHz layer and explain why.
Soc Classification level
Connected mode mobility Ping-pong RSRP/RSRQ A3 • Simultaneous activation of RSRP and RSRQ A3 handovers between two different layers may lead to ping pong HO between these layers. For example, in the previous network example case: – RSRP is better on 1800: lower frequency ->lower free space loss and penetration loss – RSRQ is better on 2600: less interference due to lower number of sites
• A UE on a 1800 site when measuring a 2600 neighbour with better RSRQ it performs HO to 2600 site. Once on 2600, the UE measures an 1800 site with better RSRP, performs HO to 2600 Exercise
1. Considering the below settings, suggest two possible solutions to avoid the ping pong (remember, operator wants to keep traffic in 2600 as long as possible): Settings for 1800 cells: – LNHOIF (2600MHz):hysA3OffsetRsrp(/Rsrq)InterFreq = 2dB – LNHOIF (2600MHz):a3OffsetRsrp(/Rsrq)InterFreq = 2dB Settings for 2600 cells: – LNHOIF (1800MHz):hysA3OffsetRsrp(/Rsrq)InterFreq = 3dB – LNHOIF (1800MHz):a3OffsetRsrp(/Rsrq)InterFreq = 3dB Soc Classification level
Connected mode mobility Exercise: inter-frequency A5 handover • An operator has an existing LTE network on 2600MHz. Additionally, they want to launch LTE on 1800MHz also. They have 20MHz BW on 2600 and only 10MHz BW on 1800, so they want to keep the traffic as long as possible on the 2600MHz layer.
• Thresholds on LTE2600 cells are: – Threshold1: 90 – Threshold3: 45 – Threshold3a: 48
• Operator wants that UEs start measuring LTE1800 cells when RSRP is worse than -100dBm.
– Identify the new thresholds that need to be considered on 2600 cells and define suitable values
– Based on new threshold values... Is there any change required in threshold3 and threshold3a values?
– Idenfity suitable thresholds for intra and inter-frequency A5 handover for the LTE 1800 cells (remember that operator’s strategy is to keep the traffic as long as possible on the 2600MHz layer) Soc Classification level
S1 handover
Soc Classification level
RL15TD
Intra LTE Handover via S1 Extended mobility option to X2 handover • Applicable for intra and inter frequency HO and only for inter-eNB HO
• DL Data forwarding via S1 • Handover in case of – no X2 interface between eNodeBs, e.g. not operative, not existing or because blacklisted usage
– eNodeBs connected to different CN elements
• For the UE there is no difference whether the HO is executed via X2 or S1 interface
• HO reasons ‘better cell HO’ (A3) and ‘coverage HO’ (A5) are supported • MME and/or SGW can be changed during HO (i.e. if source and target eNodeB belong to different MME/S-GW) Soc Classification level
Feature ID(s): LTE54
RL20
IRAT HO to WCDMA
Soc Classification level
Inter RAT Handover to WCDMA
RL25TD
RL30
• IRAT hard handover from LTE to WCDMA PS domain through S1 interface • Phases: 1. Handover initiation:
eNB starts a HO to WCDMA following a received measurement report with event B2
Max. 8 cells reported (strongest first) that create the TCL (target cell list)
2. Handover preparation:
Resource allocation on target side (E-RAB parameters mapped into PDP context)
3. Handover execution:
UE moves into WCDMA cell after receiving ‘MobilityfromEUTRACommand’ message
4. Handover completion:
Release of S1 connection and internal resources after successful HO (no timers expired)
Soc Classification level
Inter-RAT Handover to WCDMA Event B2 • Handover from LTE to WCDMA is triggered by poor LTE radio coverage and sufficient WCDMA cell radio signal quality
• Radio conditions for serving and neigbour cells are defined with event B2 Entering conditions 1. Ms + Hys < Thresh1
Leaving conditions 1. Ms - Hys > Thresh1 or
and 2. Mn + Ofn – Hys > Thresh2
2. Mn + Ofn + Hys < Thresh2
Ms
-> RSRP of serving cell
Mn
-> RSCP/EcN0 of neigbour cell
Thresh1
-> b2threshold1Utra
-> refers to signal level of serving cell
Thresh2
-> b2threshold2UtraRSCP/EcN0
-> refers to signal level of neighbour cell
Hys
-> hysB2ThresholdUtra
-> hysteresis to prevent ping-pong effect between
reportConfigInterRAT
entering and leaving conditions; parameter common for both serving and neigbour cell Ofn
-> OffsetFreqUtra
-> refers to neighbour cell only
measObjectUTRA
Soc Classification level
Inter-RAT Handover to WCDMA Event B2 Entering condition: RSRP,s < b2threshold1Utra – hysB2thresholdUtra AND utraRSCP/EcNo,n > b2theshold2UtraRscp/EcNo- offsetFreqUtra + hysB2ThresholdUtra
Soc Classification level
Inter-RAT Handover to WCDMA Flow
MME LTE, Source:CelI
Measurement Report
WCDMA, Target Cell
Triggered EventA2
RRC Connection Reconfiguration New MeasConfig used for IRAT Handover RRC Connection Reconfiguration Complete Measurement Report
Triggered EventB2 Handover Preparation
MobilityFromEUTRAcommand
HandoverToUTRANComplete
Soc Classification level
Handover Preparation Successful Handover Command
Inter-RAT Handover to WCDMA
Triggered EventA2
Triggered EventB2
Soc Classification level
eNACC to GSM
Soc Classification level
eNACC to GSM Network Assisted Cell Change to GSM • Similar feature to HO to WCDMA: • IRAT Measurements triggered via event A2/A1 (activated/deactivated) • Triggered by event B2 (although using different parameter values) • Difference: it is not a handover procedure • UE goes first into GSM RRC Idle mode and starts the RRC Connection Setup procedure in GSM
• Network Assisted: GSM system information of 2G target cell is sent to UE (giving a gain of ~1s in the process but with significant service interruption)
• Maximum number of GSM cells to be reported is hardcoded to 8
Soc Classification level
eNACC to GSM
Entering conditions
Event B2
1. Ms + Hys < Thresh1
Entering Condition:
2. Mn – Hys > Thresh2
RSRP,s < b2threshold1GERAN – hysB2ThresholdGERAN AND RxLev,n > b2theshold2RssiGERAN+ hysB2ThresholdGERAN
Soc Classification level
and
Layering Strategy. Theoretical Study eNACC procedure parameter recommendations Detailed information for parameter settings in this and other several mobil ity scenarios is available within the PKDB scenarios: http://pkdb1.emea.nsn-net.net:8080/pkdbWebToolLTE/
• Scope: • Suggest parameter settings for LTE eNACC procedure (theoretical assumptions)
• Assumptions: – Continuous GSM 900MHz coverage ensured – Partial LTE 2600 MHz coverage
• Design Goals: – – – –
Maximize users throughput
Ping-pong effect elimination Maximize UE time within LTE coverage Minimize necessary time for GSM cell measurement
– Minimize time necessary for cell reselection from LTE to GSM
Soc Classification level
Procedure Criteria Event A2 to activate GERAN measurements:
• RSRP,s < threshold2GERAN – threshold2GERAN – hysThreshold2GERAN • during a2TimeToTriggerActGERANMeas Event B2 for eNACC procedure:
• RSRP,s < b2threshold1GERAN – b2threshold1GERAN – hysB2ThresholdGERAN AND h ysB2ThresholdGERAN • RxLev,n > b2theshold2RssiGERAN+ hysB2ThresholdGERAN • during b2TimeToTriggerGERANMeas
Soc Classification level
Hysteresis values assumed to be 0 dB
Parameter Values Proposal
RSSI threshold in GERAN relative to -110
Soc Classification level
Conclusions • threshold2GERAN = b2Threshold1GERAN: when event A2 is triggered triggered (measuring (measuring for GSM neighbours) the event B2 (eNACC) could also be triggered
• Measuring time for GSM cell is limited (reducing the impact in throughput) t hroughput)
Soc Classification level
RRC Connection Release with Redirect
Soc Classification level
RRC Connection Release with Redirect Event A2 • When serving RSRP falls below threshold4 for a time a2TimeToTriggerRedirect the RRC connection is released and UE redirects to the E-UTRA or inter-RAT carrier frequency with highest priority (if several redirection objects defined) regardless of the signal strength of the target carrier
• UE capabilities are considered when performing redirect
Soc Classification level
RRC Connection Release with Redirect • It is possible to define different redirection (REDR) objects and different priorities between those objects
• eNB selects the target frequency for redirect based on the priorities configured for frequency layers
• If the highest priority layer is not supported by UE according to capabilities reported earlier, then the next highest priority layer is selected.
• Redirection is ‘blind’: UE does not measure on the target frequency for redirection before the connection is released.
• If there is no coverage in the target frequency the connection drops
• Note: Priority 1 is highest! (unlike for the cell reselection priority parameters where 7 is highest)
Soc Classification level
RRC Connection Release with Redirect Signalling
Soc Classification level
RRC Connection Release with Redirect Performance (LTE -> 3G) • Test results (FTP DL session and streaming session) show that user impact of Redirect is minimal and end user will not notice the RRC release with redirect Effects:
• FTP: couple seconds gap in the transmission is noticed while connection is redirected to 3G
• Streaming (YouTube): redirection is not noticeable. No gaps in sound/picture
Soc Classification level
CSFB Circuit Switched Fallback
Soc Classification level
CSFB to UTRAN or GSM via redirect
RL20
• Required when there is no Conversational Voice support on LTE side • Redirection from LTE to UTRAN or to GSM during the call setup. MOC and MTC setup supported
• EPC must support CS inter-working for mobility management and paging
• Redirection by RRC connection release message with a RedirectedCarrierInfo IE that enforces the UE to search for any cell first at the highest priority UTRA carrier or within BCCH carrier set for GSM
• After termination of the CS call, UEs supporting CS fallback may stay in current RAT of camp back into the LTE carrier CSFB: Circuit Switched Fallback IE: Information Element MOC: Mobile Originated Calls MTC: Mobile Terminated Calls Soc Classification level
CS Fallback Signalling Example MOC in ECM_Connected
Further examples (ECM_IDLE, MTC) in: https://sharenetims.inside.nokiasiemensnetworks.com/Overview/D4376 59035
UE needs to be IMSI attached
UE starts Initial Access procedure and sends
E xtended S ervice Reques t message with S ervice Type set to “mobile originating CS fallback” eNB sends “RRCConnectRelease” message with redirect information of WCDMA Frequency to be used for redirection
Soc Classification level
Mobility Parameter Settings Examples from real cases
Soc Classification level
Example of Mobility Parameter Settings Compilation of real cases (1/2) • Examples show that mobility related parameters are particularly project dependant even cell/area dependant and it is not possible to establish a ‘common’ value
• In order to trigger the A5 handover (coverage) it is necessary that: (threshold3a – threshold3) + 2*hysThreshold3 < a3offset +hystA3Offset
Soc Classification level
Example of Mobility Parameter Settings Compilation of real cases (2/2) • Mobility Thresholds • Thresholds are relative to -140dBm • 98 value means ‘not used’ • It is possible to further optimize the values during early drive tests and once the networks are launched
98: not used Soc Classification level
Idle mode mobility
Soc Classification level
Contents • Idle Mode Mobility – Cell Selection – LTE intra-frequency Reselection – LTE inter-frequency Reselection – Inter RAT Reselection
Soc Classification level
Cell Selection • Procedure that allows the UE to camp on a cell • UE searches for a suitable cell (belonging to the selected PLMN, not barred, belonging to a TA not forbidden and that satisfies the S-criteria):
• The UE selects a cell if Srxlev > 0
VPLMN: Visited PLMN
LNCEL: qRxLevMinOffset Typically 0 (only used when camping in VPLMN)
Srxlev = Qrxlevmeas – (Qrxlevmin + Qrxlevminoffset) – P_compensation Max(LNCEL:pMaxOwnCell - P_max from UE (*) , 0) Measured value LNCEL:qRxLevMin Typically -130dBm
(*) P_max from UE : UE class specific max. UL Tx power; 23 dBm
• SIB1 is used to transmit cell selection parameters
Soc Classification level
pMaxOwnCell (SIB1) Used to calculate P_compensation LNCEL; -30..33dBm; 1dBm; -
S – Criterion Cell Selection P_compensation = max(pMaxOwnCell – P_max from UE, 0)
• P_compensation provides a contribution only if the UE has less TX power capabilities than allowed in the radio cell
• If P_compensation > 0 the S-criteria is more difficult to achieve as Qrxlevmeas needs to be higher
• P_compensation avoids UEs camping on cells for which they have insufficient power to access (towards cell edge)
• qrxLevMin defines the cell size • qrxLevMin can be set up differently for intra frequency, inter frequency and IRAT:
I am outside
I am inside, but I have not enough power Soc Classification level
E.g. pMaxOwnCell: 33 dBm in GMC files
Cell Reselection Process Overview Measurements trigger
UE measures neighbour cells only when the RSRP signal level is below some threshold
Measurements trigger is based primarily on absolute priorities of serving and non serving frequency layers (inter freq and inter RAT)
Evaluate cell reselection criteria “R”
Different reselection cases depending on the priorities of the neighbour frequency layers (inter-frequency and inter-RAT)
Execute cell reselection
Soc Classification level
Intra frequency cell reselection
Soc Classification level
Intra frequency cell reselection Triggering Measurements • When a UE is camped on a cell it looks for better candidate cells for reselection according to sIntrasearch parameter:
• If Srxlev > sIntraSearch : UE doesn’t measure the neighbour cells • If Srxlev Rankserving cell for tReselEutr and – More than 1 second has elapsed since the UE camped on the current serving cell
RSRP,n > RSRP,s + qHyst + qOffsetCell
Soc Classification level
Intra Frequency cell Reselection Parameter Summary (1/2) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
LNCEL
sIntrasearch
Defines the threshold (in dB) for intra-frequency measurements
0...62 dB, step 2 dB
-
62
LNCEL
qrxlevMin
Minimum required RX RSRP in the cell
-140...-44 dBm, step 2 dBm
-
-130 dBm
LNCEL
qRxLevMinOffset
Affects the minimum required RX level in the cell
2...16 dB, step 2 dB
-
-
LNCEL
pMaxOwnCell
Used to calculate Pcompensation
-30...33 dBm, step 1 dBm
-
33
LNCEL
qHyst
Provides the hysteresis value in dB for ranking criteria in the cell reselection procedure.
0dB (0), 1dB (1), 2dB (2), 3dB (3), 4dB (4), 5dB (5), 6dB (6), 8dB (7), 10dB (8), 12dB (9), 14dB (10), 16dB (11), 18dB (12), 20dB (13), 22dB (14), 24dB (15)
-
1dB
LNCEL
tReselEutr
Cell reselection timer value
0...7 s, step 1 s
-
1
Soc Classification level
Intra Frequency cell Reselection Parameter Summary (2/2) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
IAFIM
intrFrBCList
Intra-frequency blacklisted cell list
IAFIM
rangeIntraPci
Number of PCIs in the range (including start PCI). Value n4 corresponds with 4, n12 corresponds with 12 and so on. The UE applies value 1 if the field is absent, in which case only the physical cell identity value indicated by start applies.
n4 (0), n8 (1), n12 (2), n16 (3), n24 (4), n32 (5), n48 (6), n64 (7), n84 (8), n96 (9), n128 (10), n168 (11), n252 (12), n504 (13), Not Used (14)
-
n8
IAFIM
startIntraPci
Lowest PCI in the range
0...503, step 1
-
8
IAFIM
intrFrNCList
Intra-frequency neighbouring cell list
IAFIM
physCellIdNcl
Unique cell identification in a neighbouring cell list
0...503, step 1
-
-
IAFIM
qOffsetCell
Cell-specific offset (in dB) that is used in the cell reselection procedure
-24 dB (0), -22 dB (1), -20 dB (2), …, -6 dB (9), -5 dB (10), -4 dB (11), -3 dB (12), -2 dB (13), -1 dB (14), 0 dB (15), 1 dB (16), 2 dB (17), 3 dB (18), 4 dB (19), 5 dB (20), 6 dB (21), …,20 dB (28), 22 dB (29), 24 dB (30)
0 dB (15)
2dB
Soc Classification level
Inter frequency cell reselection
Soc Classification level
Inter frequency cell reselection Triggering Measurements • Measurement trigger depends on the absolute priorities of the serving and nonserving layers
• The priority of the serving layer is defined in the parameter LNCEL:cellReSelPrio • For each neighbouring frequency/layer, it is necessary to define the corresponding priority: IRFIM:eutCelResPrio (7 is highest priority, 0 is lowest)
• For equal priority frequency layers it is possible to define an offset with IRFIM:qOffFrq
• If IRFIM:eutCelResPrio > LNCEL:cellReSelPrio then measurements of the neighbour cell are mandatory
• If IRFIM:eutCelResPrio RSRP n > qRxLevMinInterF +interFreqThrL Soc Classification level
-140
Inter Frequency Reselection R-criteria: Reselection to higher priority layers • If the neighbouring cell layer has higher priority than the serving layer, reselection will happen if: Srxlevneighbour > IRFIM:interFrqThrH Where: Srxlevneighbour = Qrxlevmeas – IRFIM:qRxLevMinInterF – P_compensation
Qrxlevmeasneighbour > qRxLevMinInterF + interFrqThrH (Assuming P_compensation = 0)
• The criteria above must be satisfied for a time period equal to IRFIM: interTResEut • And the UE must have been camped in the current cell more than 1 sec. interFrqThrH > interFrqThrL > threshSrvLow Soc Classification level
Inter Frequency cell Reselection Parameter Summary (1/3) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
LNCEL
sNonIntrsearch
Defines the threshold (in dB) for inter-frequency and inter-RAT measurements
0...62 dB, step 2 dB
-
2
LNCEL
qrxLevMin
Minimum required RX RSRP in the serving cell
-140...-44 dBm, step 2 dBm
-
-130 dBm
LNCEL
qRxLevMinOffset
Affects the minimum required RX level in the serving cell
2...16 dB, step 2 dB
-
-
LNCEL
pMaxOwnCell
Used to calculate P_compensation
-30...33 dBm, step 1 dBm
-
33 dBm
LNCEL
cellReSelPrio
Absolute priority of the serving layer. 0 means the lowest priority.
0...7, step 1
-
1
LNCEL
threshSrvLow
Threshold f or the serving frequency used in reselection evaluation towards lower priority EUTRAN frequency or RAT
0...62 dB, step 2 dB
-
2
LNCEL
qrxlevminintraF
IRFIM
qRxLevMinInterF
Minimum required Rx RSRP level for the neighbouring EUTRA cells on this carrier frequency
-140...-44 dBm, step 2 dBm
-
-68 dBm
IRFIM
dlCarFrqEut
eUTRAN frequency
0...65535, step 1
-
-
IRFIM
eutCelResPrio
Absolute priority of the EUTRA carrier frequency
0...7, step 1
-
5
Soc Classification level
Minimum required RX RSRP level for the intrafrequency neighbouring E-UTRA cells. (Qrxlevmin in 36.304)
-140...-44 dBm, step 2 dBm
-130 dBm
-
Inter Frequency cell Reselection Parameter Summary (2/3) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
IRFIM
interFrqThrH
Threshold used by the UE when reselecting towards a higher priority frequency X than the currently serving frequency
0...62 dB, step 2 dB
-
34
IRFIM
interFrqThrL
Threshold used in reselection towards frequency X priority from a higher priority frequency
0...62 dB, step 2 dB
-
2
IRFIM
interTResEut
EUTRA Cell Reselection Timer
0...7 s, step 1 s
-
4
IRFIM
intFrBCList
Inter-frequency blacklisted cell list
IRFIM
rangeInterPci
Number of PCIs in the range (including start PCI). Value n4 corresponds with 4, n12 corresponds with 12 and so on. The UE applies value 1 if the field is absent, in which case only the physical cell identity value indicated by start applies.
n4 (0), n8 (1), n12 (2), n16 (3), n24 (4), n32 (5), n48 (6), n64 (7), n84 (8), n96 (9), n128 (10), n168 (11), n252 (12), n504 (13)
-
n4
IRFIM
startInterPci
Lowest PCI in the range
0...503, step 1
-
200
IRFIM
physCellIdNcl
Unique cell identification in a neighbouring cell list
0...503, step 1
-
IRFIM
intFrNCList
Inter-frequency neighbouring cell list
Soc Classification level
Inter Frequency cell Reselection Parameter Summary (3/3) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
-
true
IRFIM
interPresAntP
Used to indicate whether all the neighbouring cells use Antenna Port 1. When set to TRUE, the UE may assume that at least two cell-specif ic antenna ports are used in all neighbouring cells.
IRFIM
measBdw
Maximum allowed measurement bandwidth common for all neighbouring cells on a carrier frequency. The values mbw6, mbw15, mbw25, mbw50, mbw75, mbw100 indicate 6, 15, 25, 50, 75 and 100 resource blocks respectively.
6mbw (0), 15mbw (1), 25mbw (2), 50mbw (3), 75mbw (4), 100mbw (5)
-
50mbw
IRFIM
pMaxInterF
Pmax to be used for the neighbouring E-UTRA cells on this carrier frequency. If Pmax is absent, the maximum power according to the UE
-30...33 dBm, step 1 dBm
-
10dBm
IRFIM
qOffFrq
Frequency-specific offset for equal priority EUTRAN frequencies.
-24 dB (0), -22 dB (1), -20 dB (2), …-6 dB (9), -5 dB (10), -4 dB (11), -3 dB (12), 2 dB (13), -1 dB (14), 0 dB (15), 1 dB (16), …, 20 dB (28), 22 dB (29), 24 dB (30)
0dB (15)
1dB
IRFIM
qOffCell
Cell-specific offset (in dB) that is used in the cell reselection procedure. This specifies the offset between two cells.
-24 dB (0), -22 dB (1), -20 dB (2), …, -1 dB (14), 0 dB (15), 1 dB (16), 2 dB (17), 3 dB (18), …,20 dB (28), 22 dB (29), 24 dB (30)
-
2dB
Soc Classification level
Inter RAT cell reselection
Soc Classification level
Inter RAT cell reselection • Inter RAT cell reselection is idle mode mobility from LTE to another radio access technology (RAT), e.g. WCDMA or GSM
• UFFIM is the managed object class for idle mode parameters LTE to WCDMA: – UFFIM parameters are broadcasted in the SIB6 • GFIM/GNFL are the managed object classes for idle mode parameters LTE t o GSM: – GFIM/GNFL parameters are broadcasted in the SIB7
LNBTS
LNBTS
LNCEL
LNCEL UFFIM
GFIM GNFL
UFFIM: UTRA Frequency Idle Mode Parameters GFIM: GERAN Frequency Idle Mode Parameters Soc Classification level
GNFL: GERAN Neighbours Frequency List
Inter RAT cell reselection Measurements Trigger • IRAT cell reselection procedure and related parameters are similar to those for inter frequency cell reselection
• Similar to the inter frequency case, there is the priority concept (7 is highest priority, 0 is lowest):
– The priority of serving cell is defined with LNCEL:cellReSelPrio – The priority of the neighbouring cell is defined: For WCDMA: UFFIM: uCelResPrio For GSM: GFIM: gCelResPrio
• If UFFIM: uCelResPrio/GFIM: gCelResPrio > LNCEL:cellReSelPrio then measurements of the neighbour WCDMA/GSM cell are mandatory
• If UFFIM: uCelResPrio/GFIM: gCelResPrio GFIM:gerFrqThrH
• Reselection to a lower priority RAT will happen if: WCDMA:
GSM:
Srxlevneighbour > UFFIM:utraFrqThrL &&
Srxlevneighbour > GFIM:gerFrqThrL &&
Srxlevserving < LNCEL:threshSrvLow
Srxlevserving < LNCEL:threshSrvLow
utraFrqThrH > utraFrqThrL > threshSrvLow
gerFrqThrH > gerFrqThrL > threshSrvLow
•
The criterias above have to be fullfilled during a time interval UFFIM:tResUtra for WCDMA and GFIM:tResGer for GSM
•
And the UE must have been camped in the current cell more than 1 sec.
Soc Classification level
Inter RAT cell reselection R-criteria • Srxlevneighbour is referred to the candidate cell: • GSM: Srxlevneighbour = QrxlevMeas – Qrxlevmin – P_compensation Where: QrxlevMeas = RSSI Qrxlevmin = GNFL:qRxLevMinGer
• UMTS: Srxlev = QrxlevMeas – Qrxlevmin – P_compensation Where: QrxlevMeas = CPICH RSCP Qrxlevmin = UFFIM:qRxLevMinUtra Additionally Squal > 0 required for UMTS FDD Squal = QrxlevMeas – Qqualmin Qrxlevmeas = CPICH Ec/No Qqualmin = UFFIM:qQualMinUtra Soc Classification level
LTE
UE is in LTE
UE is in 3G
Soc Classification level
3G cell reselection, signalling example
Inter-RAT cell Reselection Parameter Summary (1/3) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
LNCEL
sNonIntrsearch
Defines the threshold (in dB) for inter-frequency and inter-RAT measurements
0...62 dB, step 2 dB
-
2
LNCEL
qrxLevMin
Minimum required RX RSRP in the serving cell
-140...-44 dBm, step 2 dBm
-
-130 dBm
LNCEL
qRxLevMinOffset
Affects the minimum required RX level in the serving cell
2...16 dB, step 2 dB
-
LNCEL
pMaxOwnCell
Used to calculate P_compensation
-30...33 dBm, step 1 dBm
-
33 dBm
LNCEL
cellReSelPrio
Absolute priority of the serving layer. 0 means the lowest priority.
0...7, step 1
-
1
LNCEL
threshSrvLow
Threshold f or the serving frequency used in reselection evaluation towards lower priority EUTRAN frequency or RAT
0...62 dB, step 2 dB
-
2
UFFIM
tResUtra
UTRA cell reselection timer
0...7, step 1
-
-
UFFIM
utrFddCarFrqL
List of UTRA FDD carrier frequencies
-
-
UFFIM
dlCarFrqUtra
DL Utra frequency
-
-
Soc Classification level
0...16383, step 1
Inter-RAT cell Reselection Parameter Summary (2/3) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
UFFIM
pMaxUtra
UTRA Maximum Allowed Transmit Power
-50...33 dBm, step 1 dBm
-
-
UFFIM
qQualMinUtra
minimum required quality level in the cell in dB. Not applicable to TDD cells or GSM cells or EUTRA cells
-24...0 dB, step 1 dB
-
-
UFFIM
qRxLevMinUtra
minimum required RX level in the cell in dBm
-119...-25 dBm, step 2 dBm
-
-
UFFIM
uCelResPrio
Absolute priority of the UTRA carrier frequency Equal priorities between RATs are not supported according to [3GPP 36.304].
0...7, step 1
UFFIM
utraFrqThrH
Threshold used by the UE when reselecting towards a higher priority frequency X than the current serving frequency
0...62 dB, step 2 dB
-
-
UFFIM
utraFrqThrL
Threshold used in reselection towards the frequency X priority from a higher priority frequency
0...62 dB, step 2 dB
-
-
GFIM
tResGer
GERAN cell reselection timer
0...7 s, step 1 s
-
-
GNFL
bandInd
Indicator to distinguish the GERAN frequency band in case of ARFCN values associated with either GSM 1800 or GSM 1900 carriers
gsm1800 (0), gsm1900 (1)
-
-
Soc Classification level
-
Inter-RAT cell Reselection Parameter Summary (3/3) MOC
Parameter Name
Description
Range and step
Default value
GMC Value
GNFL
gCelResPrio
Absolute priority of the GERAN carrier frequency Equal priorities between RATs are not supported according to [3GPP 36.304].
0...7, step 1
-
-
GNFL
gerArfcnVal
Each ARFCN value explicitly listed
0...1023, step 1
-
-
GNFL
gerFrqThrH
Threshold used by the UE when reselecting towards a higher priority frequency X than the currently serving frequency
0...62 dB, step 2 dB
-
-
GNFL
gerFrqThrL
Threshold used in reselection towards frequency X priority from a higher priority frequency
0...62 dB, step 2 dB
-
-
GNFL
pMaxGer
Maximum allowed transmission power for GERAN on an uplink carrier frequency. Applicable for the neighbou ring GERAN cells on this carrier frequency. If pmaxGERAN is absent, the maximum power according to the UE capability is used.
0...39 dBm, step 1 dBm
-
-
GNFL
qRxLevMinGer
-115...-25 dBm, step 2 dBm
-
-
Soc Classification level
Minimum required RX level in the cell in dBm
Example Idle Mode Parameter settings Priorities, triggering conditions MOC
Parameter
Value
LNCEL
sIntraSearch
62
LNCEL
sNonIntrSearch
16
LNCEL
qrxLevMin
-130 dBm
LNCEL
Qhyst
3 dB
LNCEL
threshSrvLow
10
LNCEL
tReselEutr
1s
LNCEL
cellReSelPrio
7
IAFIM
qOffCell
0 dB
IRFIM
interFrqThrH
22
Relative to IFFIM:qRxLevMinInterF
IRFIM
interFrqThrL
20
Relative to IFFIM:qRxLevMinInterF
IRFIM
qRxLevMinInterF
-130 dBm
IRFIM
interTResEutr
1s
IRFIM
eutCellResPrio
6
LTE1800 layer
UFFIM
utraFrqThrL
10
Relative to UFFIM:qRxLevMinUtra
UFFIM
utraFrqThrL
10
Relative to UFFIM:qRxLevMinUtra
UFFIM
tResUtra
1s
UFFIM
ucelResPrio
5
UFFIM
qRxLevMinUtra
-119 dBm
Soc Classification level
Comments
LTE2600 layer
WCDMA layer
LTE 2600, absolute priority 7 Idle mode reselection
qrxLevMin = -130 dBm
sIntraSearch = 62
sNonIntrSearch = 16
RSRP decreases
-68
-114
-130
-140
When RSRP < -68 dBm UE starts to measure intra-freq neighbours
When RSRP < -114 dBm UE starts to measure on LTE1800 and WCDMA
LNCEL:Qhyst = 3dB
LNCEL:threshSrvLow = 10
LNCEL:threshSrvLow = 10
IAFIM: qOffestCell = 0dB
IRFIM:interFrqThrL = 20
UFFIM:utraFrqThrL = 10
IRFIM:qRxLevMinInterF= -130dBm
UFFIM:qRxLevMinUtra= -119 dBm
Reselection to LTE1800 cell will happen:
If no suitable LTE1800 cell found, then reselection to WCDMA will happen
1. When serving is below -120dBm AND LTE1800 neighbour’s RSRP is better than -110 dBm
1. When serving cell is below -120 dBm and neighbouring WCDMA cell RSCP > -109 dBm
2. For a time
2. For a time UFFIM:tResUtra = 1s
Reselection to other LTE2600 cell will happen: 1. When neighbour is 3dB better than serving 2. For a time LNCEL:tReselEutr = 1s 3. AND more than 1 s has elapsed since the UE camped in the currrent cell Rn > Rs + qoff + hys
IRFIM:intertResEutr = 1s 3. AND more than 1 s has elapsed since the UE camped in the current cell
3. AND more than 1 s has elapsed since the UE camped in the current cell
Srxlev, n > qRxLevMinInter/Utra + interFrqThrhL Soc Classification level
Exercise Idle mode reselection, priorities • Previous slide shows, for the case of LTE 2600 cells, when reselection to another LTE2600 cell, to LTE1800 cells and to 3G cells would happen based on the example settings given.
• Similarly, indicate for the case of LTE1800 when reselection would happen to: – Other LTE 1800 cells (intra frequency reselection) – LTE2600 cells (inter frequency reselection) – 3G (inter RAT reselection) • Note1: You can use previous slide (for LTE2600) as a template • Note: Consider that LTE1800 has priority 6
Soc Classification level
Example of Idle Mode Parameter Settings Compilation of real cases • Values should be used as examples rather than a reference as it is likely they are not optimized
Soc Classification level
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